Address a router with static and EUI-64 IPv6, and fix a LAN whose hosts get only link-local addresses

Steps

1. Place the devices and cable them as the Links table lists, with Copper Straight-Through cables. The switches need no configuration.
2. Configure R1's two LAN interfaces, but leave out ipv6 unicast-routing for now, as the change record does (that omission is the fault in step 4):

Router> enable
Router# configure terminal
Router(config)# hostname R1
R1(config)# interface g0/0/0
R1(config-if)# ipv6 address 2001:db8:acad:10::1/64
R1(config-if)# ipv6 address fe80::1 link-local
R1(config-if)# no shutdown
R1(config-if)# interface g0/0/1
R1(config-if)# ipv6 address 2001:db8:acad:20::/64 eui-64
R1(config-if)# no shutdown
R1(config-if)# end

3. Calculate before you look. Read G0/0/1's MAC address from the line Hardware is ..., address is xxxx.xxxx.xxxx:

R1# show interfaces g0/0/1

Build the modified EUI-64 interface ID on paper: split the MAC after the third byte, insert FFFE, and invert the seventh bit of the first byte (the bit worth 2). For example, a MAC of 0001.42a5.3b02 gives 0201:42ff:fea5:3b02, so the global address would be 2001:db8:acad:20:201:42ff:fea5:3b02. Write yours down, then compare:

R1# show ipv6 interface brief

G0/0/0 lists two addresses, FE80::1 and 2001:DB8:ACAD:10::1: enabling IPv6 always creates a link-local address, and you chose this one. G0/0/1 lists FE80:: and 2001:DB8:ACAD:20: each followed by the interface ID you calculated. Write G0/0/1's link-local address down; step 7 needs it. 4. The fault. On PC1, open Desktop > IP Configuration and set IPv6 Configuration to Automatic. Then open the Command Prompt:

C:\> ipconfig

PC1 shows a Link-local IPv6 Address beginning FE80 but no global IPv6 address. Look at the router's side of the link:

R1# show ipv6 interface g0/0/0

Under Joined group address(es), FF02::1 is there but FF02::2 (all routers) is not, and there is no line saying router advertisements are sent. R1 is not acting as an IPv6 router, so it sends no RA, and PC1 has no prefix to build an address from. Adding ipv6 enable would not help: IPv6 is already enabled on the interface. 5. The fix. Turn on IPv6 routing, then read the interface again:

R1# configure terminal
R1(config)# ipv6 unicast-routing
R1(config)# end
R1# show ipv6 interface g0/0/0

FF02::2 now appears among the joined groups, with a line reporting that router advertisements are sent. On PC1, set IPv6 Configuration to Static and back to Automatic to make it ask again, then run ipconfig once more: PC1 now has an IPv6 address in 2001:DB8:ACAD:10::/64 and its default gateway reads FE80::1, R1's chosen link-local address. 6. Calculate PC1's address. Read PC1's MAC from the Physical Address line:

C:\> ipconfig /all

Packet Tracer writes it as xxxx.xxxx.xxxx. Build the EUI-64 interface ID as in step 3, add the prefix 2001:db8:acad:10::/64, and check that it matches the IPv6 address PC1 configured for itself. Say why PC1 accepted this prefix: it is a /64, the only length SLAAC can use. 7. Configure PC2 statically: in IP Configuration, set IPv6 to Static, IPv6 Address 2001:db8:acad:20::20 with prefix 64, and as Default Gateway the link-local address of R1 G0/0/1 that you wrote down in step 3. Then from PC1:

C:\> ping 2001:db8:acad:20::20

8. On paper, write PC2's address in full, all eight groups with leading zeros (2001:0db8:acad:0020:0000:0000:0000:0020), then compress it again with lesson 4's two rules. Explain why 2001:db8:acad:20::20 is right and why a version with two double colons would be invalid.